My father’s female first cousin was 12 years older and grew up in the house next to his boyhood home.
My brothers and sister and I all regarded this first cousin as our “Aunt”.

Aunt Peggy at age 100 still had remarkable memory and brainpower.
At age 100 she met my sister and brother for lunch, walked on her own from the car into the restaurant, ordered herself a Bourbon, then proceeded to ask about by name all my brother and sister’s for updates on their lives, following up with additional questions indicating she remembered what these children were doing and living at a year or two ago.

Shortly after this restaurant meeting Aunt Peggy went in to have the “Power Cell” of her heart pacemaker changed ( these energy producers are not batteries but radioactive heat electrical generators).

They decided to give Aunt Peggy General anesthesia during the power cell change out.
They “put her under” so she would not see or hear the minor surgery. It could have been done with local anesthesia like many are.

The power cell changeout went “normally”
but when Aunt Peggy “came to” her memory was impaired very noticeably and she never really got back to how she could think before.
She died at 102 this year.

Full General anesthesia may have long term harmful effects on the elderly brain.